import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.PriorityQueue;

class Solution {
    public List<List<Integer>> kSmallestPairs(int[] nums1, int[] nums2, int k) {
        //建立一个大小为K的大根堆
        PriorityQueue<List<Integer>> maxHeap = new PriorityQueue<>(k, new Comparator<List<Integer>>() {
            @Override
            public int compare(List<Integer> o1, List<Integer> o2) {
                return (o2.get(0) + o2.get(1)) - (o1.get(0) + o1.get(1));
            }
        });
        for (int i = 0; i < Math.min(nums1.length,k); i++) {
            for (int j = 0; j < Math.min(nums2.length,k); j++) {
                List<Integer> list = new ArrayList<>();
                list.add(nums1[i]);
                list.add(nums2[j]);
                if (maxHeap.size() < k) {
                    maxHeap.offer(list);
                } else {
                    List<Integer> list1 = maxHeap.peek();
                    if ((list1.get(0) + list1.get(1)) > (nums1[i] + nums2[j])) {
                        maxHeap.poll();
                        maxHeap.offer(list);
                    }
                }
            }
        }
        List<List<Integer>> ret = new ArrayList<>();
        int size = maxHeap.size();
        for (int i = 0; i < size; i++) {
            ret.add(maxHeap.poll());
        }
        return ret;
    }
}